Apparatus for testing fluid operated switches



Dec. 13, 1949 G. H. LEONARD 2,490,821

APPARATUS FOR TESTING FLUID OPERATED SWITCHES Filed Oct. 10, 1947 5 SheetsSheet l Dec. 13, 1949 "G. H. LEONARD 2,490,821

APPARATUS FOR TESTING FLUID OPERATED SWITCHES Filed 00%,.10, 1947 5 Sheets-Sheet 2 J 3 m r a y n H O lllllx 5 ii I]!!! i q 4 0 8 6 e r 9 N 4 A. 0 w I l 52 8 2 o (I 3 H 6 2% 3 8 6 6 a .s I l l 8 WW I 9 5 ma l .7 I 7 m m ll 4 5 u J 4 8 w 4 m 6 5 I 3 I 11H IIIRW J 6 h! 5 I 5 m mm" 1 W. 4 2 8 4 9 5 2 9 O l 52 3 2 O 8 m l O l 4 4 5 y wugx 1 mwmmmm l p m mm 5 n a @w w m v mm 5 Sheets-Sheet 5 \Illlll llll 1 IIIJJIHIII Dec. 13, 1949 G. H. LEONARD APPARATUS FOR TESTING FLUID OPERATED'SWITCHES Filed Oct. 10, 194? @H Leona rd/ Patented Dec. 13, 1949 APBARATUS FOR TESTING FLUID "OPERATED SWITCHES George Leonard, Fair-field, Conn. Application October 10, 1947, Serial No. 779,088

11 Claims. (01. 7-3-4 (Granted under the act of March 3, 1883, as

amended April 30, 1928.; 870 .0. 7.57)

1 The present invention relates generally to testingapparat-us and more particularly to a hydraulic test set wherein pressure devices such, for examplaas pressure responsive electric switchesselectively may be subjected ito'pressures of widely 5 degre varying intensities, thereby :to accurately deter- A still further object is to provide a hydraulic mine their pressure responsive characteristics. test set which the pressure range thereof :is In amodern underwater mine there is generalmeasured. by :a plurality of gauges and in which ly employed a number of electric switchesef the pressure is blocked off .in sequence from the pressure responsive type. 'Iheseswitohes are congauges when the pressure applied thereto bestructecl and arranged in such a manner within comes greater than that for which the gauges the arming and firing circuits of'themine as to were calibrated. make and break various connections therein in A still ziurther object =01 thedevice is to provide predetermined sequence as themine sinks through a, hydraulic test set wherein a predetermined v01- the water. The accuracy of these switches contime 10f :oil is automatically maintained at all tributes greatly to the effectivenesslof.themine. times the test chamber of :the apparatus. It was found during the development of mines Another ohjectiis to provide a hydraulic test set of this type that a large percentage of the :hywherein the volume of liquid within the test draulic switches used therein were operating at chamber and the pressure applied thereto as well pressures considerably above .or below their reasxthe locking of the closure therefor and the exspective pressure ratings, a fact whiohnecessihausting .of the system is controlled by a single tated the testing of each switch before insta'llacontrolhandle. tion'the'reof in the mine control mechanism. A further object is to provide a hydraulic test The task of testing these switches by methods set for testing :small pressure responsive apparaheretoforeemployedproved to .be notcnly expentus wherein the closure for .the test chamber si-ve but resulted in considerable .delay'in'the .prpthereof. :is secured against removal therefrom duction of such mines, particularly when the rewhilezpressureremainsinthe chamber. spective pressure responsive character of the It is a still further object Of the invention to switches used therein-varied to any great degree. provide .a hydraulic test for rapidly testing hy- This condition generally required that each draulic electric switches or the like wherein with switch be mounted and separately tested. in expa u ply f se us pr sure from .50 to 100 paratus suitable only .for testing switches of a p s IP 1 quare inch the set is capable of particular pressure response which necessitated eralting and accurately indicating pressures of several pieces of apparatus for testing the from-.0 to 1:000 pounds per square inch. switches used i single mine of the aforede- 3', Additional objects, features and advantages of ib type, the present invention are those residing in and It is desired by themesent invention to provide relating to the novel construction and arrangea single hydraulic test set capable of wide range ment of parts forming a preferred embodiment application wherein pressures .from 0 to 10m hereof, aswill more clearly ppearifrom the {01- pounds per square inch maylbe generated and in- 4-9 lowing description, reference bein made to the dicated on a dial system for the purpose of testing mpanyin drawinss,of which: hydraulic apparatus that may vary widely in Fig. .-1 is a plan View of the preferred emboditheir pressure response. mentof theinvention as mounted within the sup- It is an object Of the present invention to ;proport therefor; vide a new and improved hydraulic test set .oa- Fig. .2 isa View partly in section and partly :in pable of providing a wide range of pressures for elevation of the preferred embodiment of the 'in- 1 testing pressure responsive apparatus. vention; g It is avfurther object to provide a hydraulic test Fig. 3 is a sectional view of the selector valve set having wide range of pressure application assembly taken along the line 33 of Fig. 2 and wherein pressure responsive apparatus such, for illustrating the valve in its Exhaust position;

2 example, .as pressure responsive electric switches, may be tested by subjecting them to pressures in excess of their pressure ratings though their respective pressure responses may vary .to a great Fig. 4 is a sectional view of the selector valve assembly illustrating the valve in its Up to line position;

Fig. 5 is a sectional view of the selector valve assembly illustrating the valve in its Hold position;

Fig. 6 is a sectional view of the selector valve assembly illustrating the valve in its Control booster position;

Fig. 7 is a cutaway view of the sleeve member showing in elevation the cap locking mechanism in the locking position thereof;

Fig. 8 is a cutaway view of the sleeve member showing in elevation the cap locking mechanism in the cap releasing position thereof;

Fig. 9 is a sectional view taken along the line 9-9 of Fig. 8 and showing the position of the spring detent, bar member, and torsion spring when the cap locking mechanism is in the cap releasing position;

Fig. 10 is an enlarged fragmentary sectional view of the pressure booster control valve assembly;

Fig. 11 is a sectional view taken along line ll-H of Fig. 2 and showing the position of the cap, cam ring, and balls when the cap locking mechanism is in cap locking position;

Fig. 12 is a view of the electric circuit diagram as used in the invention; and

Fig. 13 is an enlarged sectional view of a gauge pressure cut off valve assembly.

Referring now to the drawings and more particularly to Figs. 1 and 2, there is shown thereon a hydraulic testing apparatus, generally designated 5, which includes a body member 6 having therein a test chamber or receptacle 1 wherein high pressures may be generated for the purpose of testing pressure responsive apparatus such, for example, as a pressure responsive electric switch 8. The chamber 1 is suitable for holding a quantity of oil or other fluid, the replenishing thereof being communicated to the chamber through the connection 83 leading from a reservoir ll located beneath the body and formed by the tubular casing i2 and by disk l3, affixed to the body member in space relation thereto by the tubular supports l4, l5 and 13 preferably welded to the two members respectively.

Formed for closing the test chamber is a plug or cap piece ll having provided thereon a pair of radially projecting handle pieces l8 whereby the cap may be placed on or lifted from the chamber opening.

Arranged within the cap is an axial bore [9 wherein a suitable adapter may be secured, as by screw 2!, for supporting within the test chamber 1 the apparatus to be tested such as the pressure responsive switch 8. Aspring latch 22, pivotally connected to the edge of cap I! by screw 23, is operative to retain the switch in test position within the adapter, the latch being manually rotatable into and out of switch retaining position by the handle portion 24 thereof.

A satisfactory pressure retaining seal is maintained, where necessary, throughout the various interfitted components of the device by what is known as 0 rings 4 formed from neoprene or other suitable resilient material, the rings being arranged conventionally in grooves provided therefor in the respective parts of the device, and are operative, when compressed between two interfitting parts, to form a substantially indestructible seal therebetween.

The cap i7 is secured to the body member 6 during the testing operation of the device by a plurality of balls 26 formed preferably of steel and movable into an interlocking position between the body and annular groove 21 of the cap through radially arranged apertures 28 provided therefor in the body wall, as illustrated in Fig. 11. The balls are so arranged with respect to the cam surfaces 23 in ring 33 as to be cammed inwardly to engage groove 21 of the cap as the ring 30 is rotated to its on position, as indicated by the inscription On thereon becoming visible through the notch 3!, Fig. 1, provided therefor in the fixed dial ring 32. The balls are in their cap releasing position when the inscription Off, inscribed on the ring becomes visible through notch 31.

The cam ring 30 is adapted to be rotated to On or cap locking position by means of a manipulatable lever or handle 40 operatively connected therewith through yieldable driving connections comprising a torsion spring 34, the spring being secured to the body member 6 for movement within a recess 25 therein in such a manner as to drive the ring in a counterclockwise or looking direction through the bar member 38 which is pivotally connected to the ring as at 31' within groove 38 therein and extends into recess 25 in the body member. The bar, by bearing against shoulder 6? of groove 38 when driven against the shoulder by torsion spring 34, is operative to rotate the ring notwithstanding the pivotal connection therebetween.

Thus, the ring is normally maintained by spring 34 in the on position thereof illustrated in Fig. '7. However, as sleeve 39 to which handle 40 is secured is rotated by the handle to the exhaust position of the sleeve illustrated in Fig. 8, an angular spring member 6|, carried by the sleeve and having a detent portion M received within a circumferential groove 43 interconnecting recess 25 in body member 6, engages bar 36 therein substantially midway between ring 3i; and the point of contact 35 of spring 33 with the bar and moves the bar clockwise without pivotal movement thereof at 31, thereby to simultaneously compress spring 34 and rotate ring 30 to the off position.

When cam ring 3%! offers a predetermined resistance to movement thereof as a result of pressure remaining in the test chamber, bar 36 is first pivotally moved into contact with shoulder 61 and thereafter spring 4| slides over bar 36 whereupon it is forced outwardly of notch 42 in sleeve 39, whereby sleeve 39 may be rotated to the exhaust position without effecting release of the cap. The slipping of spring 4| by the bar leaves ring 35 in its cap locking position until such time as the pressure within the test chamber is reduced to a predetermined value. To rotate the ring after spring 6! has once slipped by bar 36, the sleeve 39 must be rotated counterclockwise until the spring if snaps over the bar, thereby enabling the ring to be rotated in the aforedescribed manner to the off position by movement of handle 40.

Sleeve 39 carries a pointer 93 which is adapted to be moved into relation with the indicia means Exhaust, Up to line, Hold and Control booster for indicating various positions of the sleeve with respect to body 3 this indicia means preferably being engraved on a fixed dial 32 secured to body 6 by the snap ring 33.

The handle 40 as it rotates sleeve 39 is also operative by means of the cam surfaces 45 and 46 on the sleeve, to control the flow of fluid within the device by positioning a selector valve assemply generally designated 1, Fig.3, :at l ar-10118 130- sl tions within "bore 48 therefor. The valve '411 is operative to selectively connect various fluid circuits throughout the device in predetermined sequence as the valve is moved within .loore 4:8, as will be more fully described :as the description proceeds.

The casing '12 within which the :body :member 6 partiail'ly arranged, is provided at its upper end with an outwardly extending flange portion 49 whereby thedevice is supported from =3, mounting panel 50 to which it is secured by screws '51. The panel is secured to a suitable supporting case or housing 52 by screws 59.

The lower 'end 'of the casing 12 is closed by .a plug member 53 preferably welded thereto in a manner to form a pressure sealing connection t-herebetween. 'Theplug 53 has arranged therein a pressure relief assembly generally designated '54 including a ball check 55 adapted to be-yieldably retained in closing position against the seat .of port 156 by spring 5:1 interposed between the ball and .an adjustable retaining plug 58. Plug '58 may be adjusted in theusual manner .to vary .the pressure response of the @ball against the valve seat by controlling the compression of spring 51 thereagainst. A notch 6 I provided in the plug 58 permits it to be distorted sufiiciently to bind in self-locking engagement with the threaded portion of the bore to thereby remain in whatever position adjusted. From the foregoing structure, it is apparent to those :familiar with such apparatus, that when the pressure within chamber 62 exceeds the force applied to the ball check 55 by spring 51, the ball separates from the seat to exhaust the pressure into the surrounding atmosphere :through port 63.

.For a :better understanding of the device and the relation of the'respective parts thereof, attention will now be directed to its operation, it being assumed for the purpose .of description, that a quantity .of air or other suitable .gas :under approximately 100 pounds pressure is supplied to the mechanism through the pet .cock assembly generally designated ill). Connection is made from the pet cock to the gas chamber 6 2 of the device through the fluid conduit within which is connected a moisture trap :65 adapted to separate from the gas entering the tester such undesirable matter as oil or moisture that might otherwise interfere with the proper operation :of the device.

The apparatus to be tested, namely the pressure responsive switch 3., is first secured within cap I 1 before the cap is locked to the body member in the manner heretofore described. The leads 66 of the switch extend .out through bore I9 of the cap to make connection with the signal circuit generally designated I19, Fig. 12, at the terminal pins 12 as illustrated in Rig. '1. The signal circuit comprises a filament transformer 13 connected in a manner to supply a voltage to a pair of signal lamps 1-4 to cause the illumination thereof when the circuit is closed thereto through contacts '16, 1'1, and 18 of switch 8 when sufiicient hydraulic pressure is applied thereto by the oil in chamber 1.

The pressure of the oil within the test chamber is controlled by the upward movement of piston 83 in response to gaseous pressure being applied to the enlarged base portion BI thereof by the gas within chamber 62. The upward movement :of the piston is operative to drive a portion of the oil from cylinder or receptacle 82, Within which the piston is slideably mounted, into the test chamber 1 through the "fluid connection 83 connected therebetween, thereby to raise the pressure within the testcham-ber in proportion to the gaseous pressure applied to the base of the piston. The ratio-of the larg-e'surfacearea 84 of the piston relative to the reduced -upper surface area '85 thereof, determining the effective pressure increase of the booster assembly,

As previously mentioned, the movement of sleeve 39 :by handle 40 is operative :by means of the cam surfaces 45 and :46 to position the selector valve 41 :at various positions within the body 5 to therebyconnect a multiplicity-of fluid circuits throughout the device in proper sequence to obtain the pressure conditions desired of the apparatus.

Fig. :3 illustrates the selector valve 41 in its initial or Exhaust position whereby any pressure within the test chamber 1 is exhausted through the reservoir LILI into the atmosphere by way of the connections 86, 8], 88, and 89 now'in fluid circuit through the valve. The connection 86 leading from the top of the test chambereonmeets with the bottom of the reservoir through the conduit 81. Thefiuid connection 88 leading from the top of the reservoir is shown in circuit with the surrounding atmosphere through the port '89. When the valve is in the Exhaust position the air supply line 90, through which is supplied the gaseous pressure for the oil fil'led portion of the system, is closed off by the 10 rings 43 and '30.

When sleeve 3.9 is moved to Up to line .pressure position :as illustrated in Fig. 4, valve 41 is operative to close oil? :the exhaust port 89 and connect air line it? with the oil filled portion of the system thereby to apply pressure to the oil in the reservoir :Tthrough connection 588 to drive a portion of the oil from the reservoirvout through the connection Bil and into the test chamber through connection 86. The quantity of oil introduced into the test chamber in this manner is governed by the volume of .air 94 trapped within the chamber atithe time of fastening the closure cap l1 thereto. This .air volume within chamber 1, when compressed by pressure being applied to the oil in the system, is reduced in volume, thereby allowing .a small quantity of oil to flow from the reservoir into the test chamber through connections 81 and to raise the oil level therein slightly above the lower edge of the admission port 92 at the terminal ofeonnection 8B. As pressure is exhausted from the system, at the completion .of the testing cycle, that portion of the oil above the'mouth of port 92 will-be rorced back into the reservoir by the expanding air 94. The oil level within the test chamber in being raised in the foregoing manner is maintained substantially constant even though a small quantity of the oil is removed therefrom on the surface of each device tested.

As valve d? .is moved to its third position, as indicated by the pointer 93 on sleeve 39 moving adjacent the inscription Pressure booster on ring dial 32, the connection86 to the test chamber is closed off whereby the air and oil therein is trapped within the chamber at line pressure. This final positioning of the valve leaves the system in condition for operating-the pressure boosting piston at by the admission of air or other suitable gas into chamber 62 'beneath'the base 8] of the piston through a fluid circuit normally closed by the ball 91, bestseen injFig. 10. Air is admitted to this fluid circuit through a plu connector '95 that is suitably threaded into" the lower disk section I3 of the body member through an opening 96 provided therefor in the casing wall. From the connector 95, the air passes through bore 91 up along the outer surface 38 of the piston 80, thence into transverse port 68 therein and down through the center 99 thereof to the ball valve generally designated I by way of the connecting bores I01, I02. The end of bore 99 is conveniently closed and sealed as by a plug I3I. At such time as the ball is lifted from its normal position across the air inlet I03 air will flow through the valve chamber I04 and bore I into chamber 62 to increase the pressure therein for driving the piston 80 upwardly against the oil in cylinder 82.

The ball 9! of the valve is normally maintained across the air inlet I03 by pin I05, the necessary force being applied to the pin by bolt I01, Fig. 2, as the bolt is urged in the direction of the pin by spring I08 under compression between the head I09 of the bolt and the bottom of bore H0 in body member 6. Bolt I01 conveniently is mounted for sliding movement within tube I4, and pin I06, in turn, is slideably mounted in a tube 68 which is slideably interfitted within tube I4 and terminates in a screw plug I0. Plug closes valve chamber I04 and is so formed as to provide a seat for ball 9 I and to retain the ball in operative spaced relation with respect to the seat, as will appear more fully hereinafter.

As handle 45 is rotated through the Pressure booster position, sleeve 39 is operative, by means of the cam surface III thereon, to lift bolt I01 clear of the pin, thereby allowing the pressure of the air within the entrance port I03 to force the ball and pin upwardly to the extent of closing the exhaust port I I2 within which the reduced section N3 of pin I36 freely moves, Fig. 10. The seating of the ball over the exhaust port allows all of the gas now entering through port I03 to flow into chamber 62 by way of bore I85. The pressure of the gas within the valve chamber I04 is suflicient, by reason of the restricting guide surface II4, to maintain the ball M in seated position across the exhaust port II2 until such time as pin I06 is forced downward against the ball by the engagement therewith of bolt I01.

Bolt I01 carries a stud H8 upon which a pair of rollers I I] are mounted for rolling engagement with slot H6 formed in body member 6. The sides I I5 of notch I56 are adapted to support and guide the rollers Ii'i as bolt I0? is lifted through the stud connection H3, the rollers operating to reduce the friction of the stud against the sides of the notch as force is applied to roller I by the cam surface I I I as sleeve 39 is rotated by handle from a direction substantially transversely to the movement of the bolt.

The increasing pressure within chamber 62, as caused by the admission of air thereinto through the now open valve I00, causes the piston 80 to move upwardly against the oil in cylinder 82 thereby forcing a portion of the oil from the cylinder up through the connection 83 and into the test chamber 1 to increase the pressure therein proportional to the movement of the piston.

As the piston 80 moves upwardly, pin I06 carried thereby is lifted into engagement with the head of bolt I01, the bolt stops further upward movement of the pin, thereby causing it, as the piston continues to rise, to press downward on ball 9| and drive the ball out of seated position across the exhaust port II2. When this occurs, the gas entering through port I03 is exhausted into the atmosphere through ports I2I and I22.

If the air is caused to be exhausted from the system faster than admitted thereto, as the result of the over travel of the piston, the consequential drop in pressure within chamber 62 will allow the piston to move downward to reduce the pres sure on pin I06 thereby allowing the ball to move upward or nearer the exhaust port II2, thereby reducing the flow of gas therethrough and movement of the piston. The handle 40, by the rotation of the cam surface III on sleeve 39, is operative in this manner to maintain the piston in whatever position desired to provide the necessary test pressure within chamber 1.

To exhaust the system at the completion of the a testing cycle, handle 40 is rotated to the Hold position, Fig. 5, thereby moving cam surface III out of supporting engagement with the stud II8 whereupon bolt I0! is moved forcefully downward by the urge of spring I08 against the pin I06 in such a manner as to drive ball 9| into seated position across the air inlet I03. When this occurs, further entrance of air into valve chamber I04 is prevented. The movement of the ball away from the exhaust port H2 allows gas from chamber 62 to exhaust into the atmosphere through ports I2I and I22, as described heretofore, whereupon the piston is gradually driven downwardly to its initial position with chamber 62 by the urge of spring I32 and by the remaining pressure within the test chamber I. After chamber 02 has been exhausted, control handle 40 may then be moved to the Exhaust position, Fig, 3, for exhausting the remaining pressure within test chamber '1 into the atmosphere by way of reservoir II.

In order to inform the operator at all times of the pressure existing within test chamber I, a plurality of gauges I23, I24 and I25 extending through an opening I33 provided therefor in sleeve member 39, are arranged about the body member 6 and mounted thereon in pressure responsive relation to the pressure within the test chamber.

These gauges, in order to obtain a more accurate reading of the pressure within the test chamber, vary in pressure response, the low pressure gauges I23 and I24, being operative to register more accurately pressures within the lower pres sure ranges of the instant device while the high pressure gauge I25 indicating pressures exceeding the response of the more senstive low pressure gauges.

To protect the low pressure gauges from pressures in excess of the maximum pressures for which they were designed, each of the gauges is provided with a pressure responsive safety valve assembly, generally designated l26, that is operative to close the fluid circuit from the test chamber to the gauge when the pressure within the chamber exceeds the maximum pressure reading of the gauge by a predetermined valve.

Valve assembly I26 includes a spool shaped piston I21 slideably arranged within a vertical bore I28 provided therefor in body member 6 at the base of test chamber 7. The base of piston I21 is exposed to the atmosphere through port I30 while the upper surface thereof is in constant communication with the pressure within the test chamber. The piston is normally retained in open circuit position adjacent the retaining ring I29 therefor by the urge of spring I30 interposed between the piston and an adjustable plug I3I, and is adapted to be moved downwardly against the spring in response to pressure applied to the 7:; piston by the fluid within the test chamber and toward a valve closingpcsitionwhen the pressure against the upper surface of the piston exceeds that of the spring by a predetermined amount. By adjusting plug 131, the initial compression of spring 130- may be'variedina manner to initially determine the maximum operating pressure of the gauge.

Normally, pressure fromtest'chamber l is communicatedto gauge 124 by way of groove 535 provided in the wall of bore I28, the groove serving to pass: the pressure beneath the upper r1ng'14-D-0f the piston and about the reduced side l-36- thereof and thence to the gauge through l e-rt s-sr.

When-the force applied to the upper surface of piston I2 1, by the fluidin the test chamber, exceedsthat-ofthe combinedforce of spring [3! and the atmosphere; the piston isdriven downwardly within bore I28: until the piston comes to rest against the upright stud ivhichformsan integral part of: the adjustable plug. ltl. This stud is adaptedtostopthe piston after the upper 0 ring 46 thereon haspassed below the lower end of groove I35; wherebythe circuit to the gauge is closed off ate-pressure corresponding to the aforesaid maximum operating pressure of the gauge. It will beunder'stood that a similar pressure cut off-arrangement, not shown; is rovided for gauge I23;

As sufficient pressure is generated within the test chamber by the operation-of the apparatus heretoforedescribed tocause operation of switch 8- under test, signal lamps M are illuminated to inform the operator of the moment of closing'of the switch contacts whereby a reading may be taken ofthe pressure indicated-on the dial system.

While this invention has been described with reference to a preferred embodiment thereof which'gives-satisfactory results, it is to be understoodby those skilled in the art to which the invention pertains, after understanding the invention, that various changes and modifications maybe-made therein-without departing from the spirit and scopeof the invention, andit is intended therefore-in the appended claims to cover all such changes and modifications.

The invention herein described and claimed may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed as new and desired to be secured by LettersPatent of the United States is:

l. A hydraulic test'set for testing pressure responsiveapparatus, including first and second liquid receptacles, fluid communicating means connecting said receptacles, a cap for closing the first said receptacle including-means for supporting the apparatus to be tested, a piston movable within said second receptacle for forcing a portion of the fluid therein through said fluid'communicating means and into said first receptacle to thereby increase the pressure therein proportional to the movement of the piston, pressure indicating means in fluid communication with the first said receptacle for registering the pressure therein, means for moving 'said piston including a gas pressure chamher for applying pressure to the base of the piston, gas communicating means for supplying gas tosaid chamber from a source of gasundel pressure, a'valve arranged in said gas communicating means andoperable-to control the flow'ofgas therethroughresponsive to movement of said piston; a handlemember, a cam surface-movable 1 0 by said handle, and a yieldable'linkage operatively connecting said valve and cam surfaceto further control operationofsaid valve upon predetermined movement of saidhandle.

2. A hydraulic test set according to claim-1 further characterized in that the pressure indicating means comprises a plurality of gauges arranged in fluid communication with the first receptacle and having different calibrated ranges of pressure response, and pressure responsive means for successively cutting saidgauges out of fluid communication with the first receptacleas the pressure therein is increased beyond the calibrated ranges of the respective gauges;

3'. A test set according to claim 1 andhaving in addition to said first and second fluid receptacles a fluid reservoir, fluid communicating means interconnecting the first receptacle and said reservoir, and a selector valve arranged within said second fluid communicating means and operable to control the flow of fluid therethrough in response to adjustment of the handle,

4. A hydraulic test set of the character disclosed including a fluid receptacle, a cap for closing said receptacle including means for supporting the apparatus to be tested, a second'fluid-receptacle in fluid communication with said first receptacle, a piston having a reduced portion movable into said secondreceptacle for forcing a portion of the fluid therein outthrough-said communicating means and into the-first receptacle to increase the pressure therein in proportion to the movement of said piston, said piston having an enlarged pressure receiving surface, means enclosing said piston surface to form a pressure chamber whereby gaseous pressure may be applied to said surface to drive the piston, as communicating means connecting said pressure chamber with a source of gas under pressure, a control valve carried by said piston operatively connected in said gas communicating means to control the flow of gas therethrough, operating means for said valve including an adjustable handle member, a cam surface movable bysaid handle member upon adjustment thereof; a linkageassembly operatively engageable by said cam surface for controlling-said valve upon a predetermined movement of the piston, and a multiple gauge system in fluid communication with the first named receptacle and operative to indicate progressively the changes in pressure therein as the gaseous pressure is changed in said pressure chamber under control of said valve.

5. A hydraulic test set of the character disclosed including a first fluid receptacle, a cap for closing said receptacle and including means for supporting the apparatusto be tested, a second receptacle in fluid communication with the first receptacle, a piston having a driving surface and a reduced portion movable into'said second re: ceptacle for forcing a portion of the fluidtherein out through said communicating means and into the first said receptacle to increase the pressure therein in proportion to the'movement of said piston, means inclosing said driving surface to form a gas pressure chamber whereby gaseous pressure may be applied to said driving surface, gas communicating means connecting said pres sure chamber with a source of gas under pressure, a control valve operatively connected in'said gas communicating means to controlthe flow of gas therethrough, operating means for said valve including an adjustable handle member, a sleeve member arranged about said-housing androtatable by said handle, a cam surface arranged" on 13 14 by said piston and adjustable variably in accordance with the movement of the piston for con REFERENCES CITED trolling the gas pressure applied thereto. The following references are of record in the 11. A testing device according to claim 10 furi file of this patent: ther characterized in that the valve means com prises an adjustable member and a coacting valve UNITED STATES PATENTS member carried by the piston and movable with Number Name Date respect to a seat thereon in accordance with the 1,905,668 White Apr. 25, 1933 pressure of the gas on the valve member and in 2,026,079 White et a1. Dec. 31, 1935 accordance with the position of the piston with 10 2,310,974 Lumm Feb. 16, 1943 respect to the adjustable member. 2,332,725 Jordan Oct. 26, 7943 2,354,562 Webb July 25, 1944 GEORGE H. LEONARD. 2,364,709 Greer Dec. 12, 1944 

